I was just wondering if there is a diesel that could fit under the hood. I'm not looking to do it soon, but I was really curious. I can see where they make them for Canada, but I don"t see any engines for sale in the US. I just really like the fuel economy of most diesels, but I haven't found any good info on a 4.0L replacement that's diesel. The closest was a 3.0L that I could only find in Canada, or the 2.8L engine that was in the Liberty diesel. I really don't think that a 5.9L or 6.0 cummins would fit well under the hood even though I did see a pic of it on the net.